Figure 5: Radiation-induced changes in urine metabolites. Comparison of metabolite levels in preand post-radiation (RT) patients using random forest analysis. (a) A predictive accuracy of 73% was obtained for classifying all GBM samples into either pre- or post-RT treatment group. 31 out of 39 preradiation samples were correctly classified, whereas 26 of the 39 post-RT samples were correctly classified (b) Multiple TCA cycle intermediates accumulated in urine with radiation treatment.